So I'm talking about roguelikes to my college's gaming club this week. Of course I'm going to start with the basics/classics of the genre and probably with either Nethack or ADOM, but I also want to show them something a little smaller or simpler; a "coffee-break" roguelike, something they might be able to make some progress in within a club meeting. I considered DoomRL, but honestly when I played that it seemed rather boring and repetitive; basically just shooting over and over and over again, which is fine for an FPS but just didn't "click" for me. Does anyone have any other suggestions?

EDIT: I guess there are some more things I initially forgot about. The game has to be free (I'm cheap), and if possible tiled (not ASCII). I'm going to show them Nethack with ASCII and would like to be able to have something different...